Arrange for only 1 of multiple branches to landing pad to be kept.

Do not remove empty landing pads (EH table needs to be updated)

llvm-svn: 37375
This commit is contained in:
Dale Johannesen 2007-05-31 21:54:00 +00:00
parent e6ccb6c5ed
commit 1a401e68a8
1 changed files with 13 additions and 4 deletions

View File

@ -684,18 +684,26 @@ static bool CorrectExtraCFGEdges(MachineBasicBlock &MBB,
}
}
MachineBasicBlock::pred_iterator SI = MBB.succ_begin();
MachineBasicBlock::succ_iterator SI = MBB.succ_begin();
bool foundPad = false;
while (SI != MBB.succ_end()) {
if (*SI == DestA && DestA == DestB) {
DestA = DestB = 0;
if ((*SI)->isLandingPad())
foundPad = true;
++SI;
} else if (*SI == DestA) {
DestA = 0;
if ((*SI)->isLandingPad())
foundPad = true;
++SI;
} else if (*SI == DestB) {
DestB = 0;
if ((*SI)->isLandingPad())
foundPad = true;
++SI;
} else if ((*SI)->isLandingPad()) {
} else if ((*SI)->isLandingPad() && !foundPad) {
foundPad = true;
++SI;
} else {
// Otherwise, this is a superfluous edge, remove it.
@ -832,8 +840,9 @@ void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
++FallThrough;
// If this block is empty, make everyone use its fall-through, not the block
// explicitly.
if (MBB->empty()) {
// explicitly. Landing pads should not do this since the landing-pad table
// points to this block.
if (MBB->empty() && !MBB->isLandingPad()) {
// Dead block? Leave for cleanup later.
if (MBB->pred_empty()) return;